The role of katanin p60 in breast cancer bone metastasis

Abstract

p60 is a subunit of katanin involved in microtubule-severing. Previous studies of p60 were primarily focused on microtubule regulation and cell cycle regulation. More recent research has demonstrated that katanin p60 possesses a function in prostate cancer bone metastasis; however, its role in breast cancer bone metastasis remains unclear. In the present study, immunohistochemistry was used to analyze the expression of katanin p60 in primary and bone metastatic breast cancer. The role of up- and downregulated katanin p60 was investigated using cell proliferation, and migration experiments. Overall, katanin p60 was highly expressed in breast cancer bone metastatic tissue compared with primary tumor tissue. In breast cancer cells, overexpression of katanin p60 inhibited cell proliferation, but promoted cell migration, whereas silencing katanin p60 expression promoted cell proliferation but inhibited cell migration. Overall, the present study indicated that katanin p60 serves a role in cell proliferation and migration, and thus may be a novel therapeutic target for prevention of breast cancer metastasis.

Keywords: bone metastasis; breast cancer; cell proliferation; katanin p60.

Figure 1.

Immunostaining of katanin p60 in normal breast glands, primary breast and bones metastatic tumors (n=10/group). (A) The expression of katanin p60 in healthy breast, primary breast cancer and bone metastatic tissues. The red arrows indicate the enlarged area. (B) Quantitative analysis demonstrated that the expression of katanin p60 protein increased significantly in primary and bone metastatic tissues compared with healthy breast tissue, **P<0.01 vs. normal breast..

Figure 2.

Effect of up- or downregulation on MDA-MB-231 and MCF-7 cells. Western blot demonstrating the effects of pcDNA3.1/KATNA1 or shRNA-KATNA1 transfection on katanin p60 protein expression in (A) MDA-MB-231 and (B) MCF-7 cells. *P<0.05 vs. pcDNA3.1 or shRNA-NC. Reverse transcription-quantitative polymerase chain reaction was used to determine the expression of katanin p60 following transfection with pcDNA3.1/KATNA1 or shRNA-KATNA1 in (C) MDA-MB-231 and (D) MCF-7 cells. *P<0.05 vs. pcDNA3.1 or shRNA-NC. shRNA, short hair pin RNA; NC, negative control; KATNA1, katanin catalytic subunit A1.

Figure 3.

Katanin p60 in cell proliferation. Upregulated expression of katanin p60 inhibited the proliferation of (A) MDA-MB-231 and (B) MCF-7 cells. *P<0.05 vs. pcDNA3.1. Cell proliferation was increased in (C) MDA-MB-231 and (D) MCF-7 following transfected with shRNA-KATNA1. *P<0.05 vs. shRNA-NC. shRNA, short hair pin RNA; NC, negative control; OD, optical density; KATNA1, katanin catalytic subunit A1.

Figure 4.

Regulation of katanin p60 levels adjusted cell migration. (A) The number of cells stained with crystal violet demonstrated the capacity of migration in each group. The number of cells transfected with pcDNA3.1/KATNA1 increased notably, and overexpression of katanin p60 significantly increased cell migration in MDA-MB-231 and MCF-7 cells. *P<0.05 vs. pcDNA3.1. (B) After transfected with shRNA-KATNA1, the number of cells decreased and silencing of katanin p60 significantly inhibited cell migration. *P<0.05 vs. shRNA-NC. shRNA, short hair pin RNA; NC, negative control; KATNA1, katanin catalytic subunit A1. The length of the scale bar was 100 µm.